This Venereal Disease Research Program Project has four component project: 1. Epidemiology and pathogenesis of gonorrhea: Auxotyping and serotyping of N. gonorrhoeae are used to study the epidemiology of gonorrhea. The relationship of oral contraceptive use to risk of gonorrhea, and the epidemiology, etiology, and pathogenesis of certain clinical manifestations of gonorrhea, such as salpingitis, Fitz-Hugh Curtiss syndrome, and disseminated gonoroccal infection are being studied. An assay has been developed for measuring phagocytosis of N. gonorrhoeae. 2. Genetic determinants of gonorrhea: Recombinant DNA technology is being used to study the genetic and antigen composition of N. gonorrhoeae and Chlamydia trachomatis. Plasmids of N. gonorrhoeae, C. trachomatis, and H. ducreyi are being characterized. 3. Nongonococcal urethritis and related genital infections: This project addresses the epidemiology, immunology, pathogenesis, diagnosis and therapy of Chlamydia trachomatis infections and the etiology of NGU. 4. Treatment and pathogenesis of Hemophilus vaginitis: The etiology, pathogenesis, diagnosis and therapy of nonspecific vaginitis are being studied. Pilot studies of Trichomonal and Candidal vaginitis have been started.